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66

Sometimes we do, and the phenomenon is called a light echo. What you're looking at there is NOT moving gas. It's an "echo" exactly as you describe. The problem is that you need a pulse of light. If you have a constant stream of light, the "light echos" will be exactly like what you see in fog on earth.


24

It would be possible to see the progress of photons through space if the light pulse were exceedingly intense, and if the dust cloud from which they reflect were positioned and shaped to reflect the light toward us. Rather than shooting a beam from Point A to Point B, it would be better if the light source were between us and the dust cloud, as light ...


12

If some of the light is reflected off the dust at such an angle that it is diverted to reach the observer, the observer will see that light. However, those specific photons reaching the observer will not reach B (unless they are reflected there by the observer). Similarly, unless the observer is at point B (which is not the case in the question as asked), ...


8

Using a camera that can capture "Motion at a Trillion Frames Per Second", this can be done at the laboratory scale. The technique used has been called femto-photography. (Image credit to Ramesh Raskar, Associate Professor, MIT Media Lab) Of course a camera that literally takes one trillion full frames per second is totally impossible with today's ...


7

Let's say you build a ping pong ball counter. It increments the count every time a ping pong ball hits the sensor. You throw a ball, and it hits the sensor: Detected! You throw a ball across the sensor from left to right... no detection, because you didn't hit the sensor. Your eyeball is a light sensor, which creates pictures from the light that hits ...


4

My masters project was on something like this (though with hydrogen alpha emission lines for gas clouds between galaxies rather than dust between stars) and the answer in that case (and almost certainly in this one too) is that you can't see it because it's just too dim, though using hundreds of telescope hours can get you close (maybe). Again, this is not ...


2

The video is of the Atacama Large Millimeter Array, and this is an atronomical interferometer. Interferometers work by combining the signal recorded by many individual dishes to reconstruct the original image. To make this work all the dishes have to be pointed towards the same object, and that's why the video shows them moving in sync.


2

What you are seeing is the ALMA http://www.eso.org/public/teles-instr/alma/ which is an array of radio telescopes whose data can be combined to simulate the performance of a much bigger radio telescope. So the reason they're moving in synchrony is that they are all looking at the same target.


2

One of the routine methods for detecting the presence of chemical compounds is infrared spectroscopy, and you'll find infrared spectrometers scattered around any terrestrial orgganic chemistry lab. Organic compounds absorb infrared light at characteristic frequencies, and those absorption lines can be used as a fingerprint to detect the molecule. Exactly ...


1

According to the classic story "A Martian Oddyssey" By stanley G. Weimbaum, the planet Mercury would not be visible with the naked eye from Mars (appearing much closer to the glare of teh Sun). Thus when the Martian Tweel draws the moon in orbit around the third planet and Deimos and Phobos in orbit around the fourth planet Dick Jarvis believed it proved ...


1

In the early days of the solar system, it is generally believed , as the comment above implies, that it was a place of constant collisions. The moon may have been part of the Earth, there is strong evidence for that, and an impact is the most probable way that it would be have been able to became a separate orbiting body. For the giant planets, Jupiter ...


1

All the answers serve very good explaining why all the telescopes are synced. The only question which remains is that why we are using 4 telescopes or any number of telescopes for that matter. Actually, the quality of data collected increases with the diameter of the telescope. So, they place many telescopes in an array to increase the diameter of the ...



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